1. Field of the Invention
Aspects of the present invention relate to an organic light emitting display device (OLED).
2. Description of the Related Art
An organic light emitting display device (OLED) is a self-emissive display device, in which a voltage is applied to an organic thin layer including an anode, a cathode, and an organic emission layer (EML) interposed between the anode and the cathode, so that electrons and holes recombine in the organic EML, to emit light. In comparison with a cathode ray tube (CRT) or a liquid crystal display (LCD), an OLED may be lighter, thinner, have a wider viewing angle, a faster response speed, and lower power consumption.
A full-color OLED may exhibit different luminous efficiencies in different sub-pixels, that is, according to the colors of the emission materials therein. Typically, a green (G) emission material may have a higher luminous efficiency than a red (R) emission material or a blue (B) emission material. The R emission material may also have a higher luminous efficiency than the B emission material.
Thus, various conventional methods have been used in an attempt to produce OLEDs having a high luminous efficiency and luminance, by forming organic EMLs or organic thin layers, of respective sub-pixels to different thickness, so as to vary the optical thicknesses of the sub-pixels. However, the formation of the organic EMLs or organic thin layers, of the respective sub-pixels to different thicknesses involves a complicated process involving the use of a fine metal mask, which leads to an increase in failures, such as stains or dim spots, thus reducing yields.